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WSDL grounding

From: Sheshagiri, Mithun <Mithun.Sheshagiri@hp.com>
Date: Tue, 29 Jul 2003 14:29:50 +0100
Message-ID: <5E13A1874524D411A876006008CD059F0738367C@0-mail-1.hpl.hp.com>
To: "'www-ws@w3.org'" <www-ws@w3.org>
Hi all,

There seems to be problem when grounding DAML-S in WSDL. If one describes 
a atomic process with conditional output like congoProcess:LocateBook, 
then there seems to be no straight forward way of implementing this in 
WSDL.

When describing operation in WSDL, a single input and a single output can 
be specified for the Request-Response transmission primitive. What we need 
is a primitive that would let us specify two outputs and the actual output 
can be oneOf the two outputs. Also note that there could be scenarios 
where the two outputs could be different data-structures.

Consider the following service:

input: BookName
output: oneOf(output1,output2)
condition: BookInStock
output1: BookInfo
output1: BookNotInStock

If BookInStock is grounded to True then, BookInfo is the output else the 
output is an message BookNotInStock. 


These are some ways of grounding the service:
1. Make daml-s-parameter point to the ConditionalOutput class of the 
AtomicProcess. To do this, we will need a module that inspects the content 
of the message received and disambiguates the outputs for the upper 
layers.

2. Use the wsdl:fault to define BookNotInStock
Not a good option since the semantics of fault is too strong and not 
appropriate to describe something like BookNotInStock output, but there 
can easily be other cases where this construct can be useful. In general a 
service could have two non-faulty outputs and WSDL:fault cannot capture 
this. 

3. Ground an AtomicProcess to two WSDL:operations. One with output as 
BookInfo and other with the output BookInStock. At the moment, each 
AtomicProcess grounds to a single WSDL:operation.

4. Describe services to eliminate conditional outputs/effects altogether. 
The checking of the Condition can be defined as an AtomicProcess and then 
define two more atomic processes that handle the True and False cases of 
the Condition.

Comments/Clarifications?


Some minor corrections
1. File: CongoProcess.daml and CongoProcess.owl

<rdf:Property rdf:ID="nameBookInCatalogue">
  <daml/owl:domain rdf:resource="#BookInCatalogue"/>
  <daml/owl:range rdf:resource="&xsd;#string"/>
</rdf:Property>

BookInCatalogue in the above bit should be BookInCatalogueP


2. File: CongoProcess.daml and CongoProcess.owl
In the LocateBook AtomicProcess:
LocateBook is defined as the disjointUnionOf LocatedBookOutput and 
NotFoundBookOutput. LocatedBookOuput is the ConditionalOutput with 
coCondition-InCatalogueBook and  NotFoundBookOutput is the 
ConditonalOutput with coCondition-NotInCatalogueBook. This linking between 
ConditionalOuput and the corresponding coCondition is not shown. I think 
you might want to be put property restrictions in the definition of 
LocatedBookOutput and OutInCatalogueBookDescription. 

3. The property conditionValue has been used to link Conditon and 
TestValue. However, the definition of the property conditionValue has 
range TestCondition which in turn is a subClassOf of Process.


Thanks guys!
mithun
http://www.cs.umbc.edu/~mits1 <http://www.cs.umbc.edu/~mits1> 


Mithun Sheshagiri
HPLabs, Bristol
http://www.cs.umbc.edu/~mits1 <http://www.cs.umbc.edu/~mits1> 
Mobile: (044) 07787970209
Received on Tuesday, 29 July 2003 11:26:24 GMT

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